A conventional socket tool is shown in FIG. 6 and generally includes a shank 90 having a rectangular end on one end of the shank 90 and a bar 900 is connected to the other end of the shank 90. The rectangular end has a ball 92 embedded in a side thereof so that when a socket 91 is mounted to the rectangular end, the ball 92 urges against an inside of the socket 91 so that the socket 91 is positioned on the rectangular end. The ball 92 is biased by a spring which is received in a recess in the side of the rectangular end. It is difficult to remove the socket 91 from the rectangular end if the spring force so large that the user will take a great effort to overcome the engaging force between the ball 92 and the socket 91. On the contrary, if the spring force is small, the socket 91 could drop easily.
The present invention intends to provide a tool having a sleeve that controls an engaging member so that the engaging member can be received in a slot by operating the sleeve when the socket is to be mounted to or removed from the tool.